Hi,
I hope to have posted this on the appropriate section. I have just signed as new member so bear with me if I do not know how this forum works.

I have just purchased a USB Oscilloscope DSO-2090 and am having a hard time making it work. I have not used an oscilloscope since university and never used a USB Osc. The user manual this unit came with it is unseless. Perhaps assumption is made buyer is familiar with how to use it? Here it is my problem.

The unit came with one cable that connects Osc. to computer but at the computer end has 2 usb one red and one black. I connected only black usb to the computer and the light is flashing (on Osc.). I tried to make measurements after installing software but it is not measuring correctly. Measuring DC signal and shows sine wave on the screen!!!! Voltage measurement is also off. Should I connect both USBs (black and red)to the computer? I was tempted to do this but did not want to take risks as it may ruin Osc.

Does anyone know where I can download a manual on how to connect this to computer and how to take measurements? Your help is appreciated.
Morel

It says nothing about the two specific plugs. It only says plug the usb into the computer!!!! It does not explain the function of each plug. Maybe is comon knowledge!! I hope there is a manual somewhere to explain how to connect and properly use this unit.

I found out that one of the usb (red) is for additional power in case the black does not supply enough. And that Oscilloscope light is supposed to be flashing. I might have to calibrate probes (for the first time). This may be the issue. Anyone has any instructions on how use software and take measurements on this unit? Thanks,
Morel

a tad off topic, but, i bought the inexpensive usb scope from Parallax

it kinda sucked. i started with ver. 4 of the software. lots of nice features but at higher freq the usb updating became a issue. then when ver. 5 came out i noticed issues with 5. changing scales were F'd up, looked exactly like what happens when its not calibrated. i went through calibration steps about 10 times before giving up. their support team couldnt figure out why. some other problems in 5.x were suppose to be fixed in 5.xy but they use some 3rd party code writer and updates were taking forever (on the order of 6-8 months). i also find it odd that the Parallax site says to use the older ver. 4 if you want those "other" features...... why the ver. 4 features are not in ver. 5 is beyond me.....

anyways, i decided to use the parallax usb scope as a novelty device. the really good usb scopes cost around $1500. instead i bought a Owon dso 30MHz portable with battery lcd dual channel scope..... really useful for me since i do automotive work with it..... i connect scopes to pc's with skepticism...

some googlin revealed:
"1. A line connects to the USB front-USB port of your computer (black line communications / red power lines - can be used only black, mainly to prevent supply shortfall)."

Hi all.
I have decided to join this group because I just got a DSO-2090 USB oscilloscope yesterday and I have been enjoying it a lot. I see little other discussions on the Web about this device and it would be good to share experience and questions.

I am running the DSO on a Thinkpad T43 under Windows XP Pro. I was surprised at how effortless the installation was. Based on trying the 1 KHz test signal, a variable frequency signal generator, and a fixed 50 MHz oscillator (beyond the 40 MHz bandwidth limit) I am really impressed with the device. However, I need to plahy with it a lot since the documentation is pretty basic.

I too concluded that the double ended USB cable was just to supply enough power. The pins at the red and black ends are simply wired together. I am just using an ordinary USB cable with no problems.

It appears that some buttons are presented backwards from customary usage. For example the run and pause buttons. Similarly the menu items for turning on and off the cursor lines. But almost everything seems to work. I am a bit puzzled about some features however.

For example, there is a question regarding interpolation mode. The HTML manual indicates that this is accessed via Menu>Display>Interpolation mode. In my version of the code, at least, this does not seem to be the case. There is a button Line Mode, next to line or dots. However, this button does not seem to affect anything. Perhaps it is active only under some condition I have not played with.

In general I am enormously impressed with this device. Most of the features I have played with seem to work, at least after some experimenting. Since there seems to only a limited amount of information available I am glad to have to opportunity to learn from the experience of others, and perhaps pass on what I have discovered.

Playing with the DSO-2090 a bit more I now see that the interpolation feature works as advertised. The is, however, now obvious visible indicator of the mode. However, at sufficiently high sweep rates (say 40 ns/div) the effect of the interpolator is quite clear. Both the button and the menu selection simply step the interpolation mode through the sequence: sine, linear, square. It seems to me that linear interpolation works best.